github.com/riscv/riscv-go@v0.0.0-20200123204226-124ebd6fcc8e/test/switch5.go (about)

     1  // errorcheck
     2  
     3  // Copyright 2016 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  // Verify that switch statements with duplicate cases are detected by the compiler.
     8  // Does not compile.
     9  
    10  package main
    11  
    12  import "fmt"
    13  
    14  func f0(x int) {
    15  	switch x {
    16  	case 0:
    17  	case 0: // ERROR "duplicate case 0 in switch"
    18  	}
    19  
    20  	switch x {
    21  	case 0:
    22  	case int(0): // ERROR "duplicate case 0 in switch"
    23  	}
    24  }
    25  
    26  func f1(x float32) {
    27  	switch x {
    28  	case 5:
    29  	case 5: // ERROR "duplicate case 5 in switch"
    30  	case 5.0: // ERROR "duplicate case 5 in switch"
    31  	}
    32  }
    33  
    34  func f2(s string) {
    35  	switch s {
    36  	case "":
    37  	case "": // ERROR "duplicate case .. in switch"
    38  	case "abc":
    39  	case "abc": // ERROR "duplicate case .abc. in switch"
    40  	}
    41  }
    42  
    43  func f3(e interface{}) {
    44  	switch e {
    45  	case 0:
    46  	case 0: // ERROR "duplicate case 0 in switch"
    47  	case int64(0):
    48  	case float32(10):
    49  	case float32(10): // ERROR "duplicate case float32\(10\) in switch"
    50  	case float64(10):
    51  	case float64(10): // ERROR "duplicate case float64\(10\) in switch"
    52  	}
    53  }
    54  
    55  func f4(e interface{}) {
    56  	switch e.(type) {
    57  	case int:
    58  	case int: // ERROR "duplicate case int in type switch"
    59  	case int64:
    60  	case error:
    61  	case error: // ERROR "duplicate case error in type switch"
    62  	case fmt.Stringer:
    63  	case fmt.Stringer: // ERROR "duplicate case fmt.Stringer in type switch"
    64  	case struct {
    65  		i int "tag1"
    66  	}:
    67  	case struct {
    68  		i int "tag2"
    69  	}:
    70  	case struct {
    71  		i int "tag1"
    72  	}: // ERROR "duplicate case struct { i int .tag1. } in type switch"
    73  	}
    74  }
    75  
    76  func f5(a [1]int) {
    77  	switch a {
    78  	case [1]int{0}:
    79  	case [1]int{0}: // OK -- see issue 15896
    80  	}
    81  }
    82  
    83  // Ensure duplicate const bool clauses are accepted.
    84  func f6() int {
    85  	switch {
    86  	case 0 == 0:
    87  		return 0
    88  	case 1 == 1: // Intentionally OK, even though a duplicate of the above const true
    89  		return 1
    90  	}
    91  	return 2
    92  }
    93  
    94  // Ensure duplicates in ranges are detected (issue #17517).
    95  func f7(a int) {
    96  	switch a {
    97  	case 0:
    98  	case 0, 1: // ERROR "duplicate case 0"
    99  	case 1, 2, 3, 4: // ERROR "duplicate case 1"
   100  	}
   101  }